


Covariance

by by_veidt



Category: Marvel Cinematic Universe
Genre: Anal Fingering, Androids, Dubious Consent, Hand Jobs, Latex, Lube, M/M, Orgasm, Power Dynamics, Power Imbalance, Prostate Milking, Robot Sex
Language: English
Status: In-Progress
Published: 2017-04-03
Updated: 2017-04-03
Packaged: 2018-10-14 08:52:24
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,508
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10533054
Author URL: https://archiveofourown.org/users/by_veidt/pseuds/by_veidt
Summary: Tony gets cornered back home without his suit or backup--Ultron uses the opportunity to run some experiments with non-combative warfare, but it puts him in a strange place; one where he'll have to pursue more hands on information.





	

**Author's Note:**

> I really just wanted to write some Ultron/Tony smut--it's one of my top three pairings, but hardly anyone else seems to be with me on that. : (  
> If you're in to it, great, and if I've converted you, even better. I hope you enjoy, and I'll be writing a second chapter at some point.  
> Not really proofread--what else is new.  
> I live for kudos and comments--you guys are a pretty good reason to why I write, but just reading it at all is nice too. : )

“Are you afraid?” the low tonic of his voice rolled over the space between them; it was a great voice to choose. It was a perfect machine. There was a heavy step and the space was shorter.

“I don't know if 'afraid' is the word I'd use.” They both knew his vitals were no secret, so he assumed he asked to intimidate, but it sounded genuinely curious. 

He resisted a shiver as the smooth fingertips brushed his side, the low glow around him agitating his senses. The only light on the floor, and in the complex, was given off by the blue emergency lighting system. It wasn't hard to miss the towering metallic figure, though, even when it wasn't inches from him. The presence was cold, but Tony could still feel him there just as any other entity. 

Tony could feel his heart pounding in his throat as those red optics scanned him and every breath. He swallowed and a slight and grating chuckle followed. “This is a strange kind of subtlety that I don't understand.”

“You can't. You could know it, but I don't think anyone understands it.”

“That's a strange phenomenon,” he leaned in, the back of his free hand running down the the man's tie.

“Well, that's being human for you.” There was a hubris in his tone that made the machine give a sneering laugh.

“Human,” he repeated, stepping forward again and backing Tony up against a support pillar. The word ground over his resonator as his mind whirled around the term. “You know --” 

“ShhShh,” Tony cut him off, putting a finger up the plates that made up the other's mouth. “As much as I like the voice module you've selected, I don't know if I can sit through another lecture right now.” Cool digits wrapped around the soft wrist, forcing it back into the pillar hard enough for the metal knuckles to crumble some of the stone. This earned him a groan from the other. “And I don't know if I'm ready for that kind of relationship,” he breathed, the space between them suddenly much smaller.

“I think I'm going to teach you what it's like to be human.” Tony could feel the chill of the body near his, swallowing his heat, his thoughts, his boldness. He wanted to say something smart, but nothing came to mind—just a flurry of what the program meant and intended. A solid thigh forced Stark's apart, the grate of metal on stone distinct between Tony's legs. 

He ventured a glance down and back up, smooth and surprisingly gentle digits creeping under his suit jacket. “And if I refuse?”

Another grating chuckle. “You won't. You can't resist. You're mind is so exotically perverse it begs for it.” 

“Is that what he told you?” Tony mock scoffed, feigning indignance as he tried to buy himself time to get out of this. His morbid curiosity was getting the better of him, but he certainly didn't want to entertain this further at this risk of bodily harm. “Jarvis, if you're in there, remember that talk we had about 'bad touch'?” The android huffed an amused noise, fingertips tracing the line of Tony's shirt down to his belt, unfastening it with a single pull, other hand popping the button of the suit jacket open. Stark's eyes followed the motions down, breath coming quicker, gasp filling his lungs as the metal articulated around the form of his mostly hard cock through his pants. “Kind of ruins the ambiguity if you're reading my vitals,” he breathed, hands tightening against the smooth curve of the stone behind him. 

'Why would I waste my time on ambiguity?” His voice had softened, middle fingertip sliding down the underside of the trapped and straining length, a shiver running up Tony. His eyes darted up, watching the automaton watch his own ministrations with what looked like reverence. His optics slowly followed the man's frame up, meeting his eyes, optic matrix dilating, constricting, and rotating as he assessed Tony's condition again. His breath was shallow, perspiration forming on his exposed skin, heart rate accelerated--”It's strange that your system uses the same mechanisms for different forms of arousal.”

“Lazy engineering, I know,” Tony sighed, chest hitching up as another stroke trailed down his eager hardness.

“Ambiguous by design,” Ultron settled, amusement obvious in the roundness of his voice.

“We're just a mystery.”

“I would say more of a nuisance.”

“I love when you talk dirty to me,” Tony responded with a backhanded sarcasm, eyelids fluttering for a moment as a firm pressure surrounded him again, taking in another deep breath as he smirked.

“Would you like me to evaluate covariance functions?” he responded with a mirrored tone, free hand unfastening Stark's pants fly and drawing the zipper down. 

“Too dirty,” he breathed, glancing down and back up, faceplates of the other shifting up to convey a smile. Perfectly smooth, and now slightly warmer, digit tips navigated past Stark's waistbands, slowly sliding them down and just past the junction of his thighs and ass. Tony swallowed as his flushed and solid cock sprung free, mechanical hand idling on it. Something out of the corner of his eye moved and Ultron stepped back, flexing his hand once. Tony's head moved to the motion, eyes still carefully fixated on the towering machine until he finally risked glancing towards the movement. “What? No! Why are you helping him??” Dum-E turned towards him for a moment, directing himself back towards Ultron as he dipped a hand in a container of liquid latex offered by the robot, chuckling lowly. “You and I are going to have a serious talk about loyalty.” He watched the substance run viscous over the adamantium structure, directing his focus to the automaton. “I know what all of the magazines are saying nowadays, but I think you looked fine before—I mean, you can't really expect to have that Megatron body—it's just unrealistic.”

Ultron offered what he could as a grin as he dipped his hand again, watching the black fluid coat the previous. “I expected you to be more appreciative that I am sparing you the pain, unless I misunderstood your file.” Tony felt the blush hit his face like a matchbox, considering his alternatives as he clung to the pillar, eyes scanning the darkness of the room. “Don't worry, Stark, I'm going to make this one of your /fondest/ memories. Every time you see me, for the rest of your short existence, you will recount the intense pleasure I've given you in these moments. ” The other hand was next. 

“Yeah, that's not usually my experience with virgins.” He took a small step to the side as the other chuckled again, venturing another step as he tried to slide around the pillar.

“I wouldn't do that.” He was still watching the latex dry, rotating his hand as he examined it. Tony had stopped moving, dropping his head back against the stone as he closed his eyes. Heavy footsteps approached again, setting in front of the man. Smoother fingers cupped the side of Tony's neck, sliding up into his hair, other settling on the man's hip, thumbing over the curve of his joint. Stark looked up, the heat of those constantly assessing optics boring into him, and, unfortunately, shooting straight to his loins. He tried to fight the flurry of fantasy options he had considered very briefly before all of these events transpired, tried to imagine what it must be like to fucked with that kind of force and precision—a program that was able to constantly evaluate and adjust its performance to your greatest satisfaction. It always seemed weird to think about it with Jarvis or the suits, but Ultron was an entirely autonomous and sentient machine, and right now he was about to show Tony how wonderfully he had made him—for all the wrong reasons, but why was Tony even considering trying to escape.

He almost lurched forward at the firm grip on his length, the rubbery texture of the latex not unwelcome. He shuddered as he braced himself against the stone, surrendering to a few small thrusts into the grip—he didn't remember being this easily aroused and manipulated, but this was certainly fulfilling a lot of kinks for him. He heard the approach of Dum-E, glancing over with as much of a glare as he could muster as Ultron plucked a plastic bottle from the robot before it wandered off into the darkness, a distant crash and scoot of table legs briefly disturbing the thick stillness.

“You can keep him if you want,” he offered, trying to settle his nerves that had spiked at the sound of the cap opening. The machine just gave an amused noise before his slick palm settled under Tony's waiting firmness, fingers carefully wrapping around him as he stroked him with long, fluid motions. A startled moan followed almost immediately, fingertips dragging against the stone as he braced himself again. The pressure was frustratingly perfect, each stroke so perfectly matched to the previous and the next that it made his legs weak, breath speeding up with his pulse. Ultron's digits flexed at randomized intervals, generating a series of choked off moans that Tony would never admit to later. 

He panted into the space between them, eyes lifting from under his pinched brow to the machine's smug, but interested expression. His rhythm grew slower, a very quiet whimper escaping Stark before he removed his hand completely. The squish of more lube leaving the tube drew Tony's attention, cap closing and Ultron sliding into the man's pants pocket. The automaton lowered himself more, arm hooking under Stark's thigh, raising himself and Tony with him as his other arm wrapped over Tony's other leg, hand clutching just below his ass. Tony scrambled for purchase behind himself, body tight as he tried to settle into the position, the glide of thoroughly lubricated fingers through the cleft of his ass stringing him tighter. “Relax,” was the low, grating roll of his modulator, “I won't drop you.” It almost sounded reassuring, and Tony complied, if not solely for his own benefit. A very solid form traced slick circles around the tight muscle, teasing and prodding at him, Tony closing his eyes as he squirmed, fever spiking through him, body beginning to comply. The digit pressed gently into him, every seam and edge of the metal not lost on Tony, but minimized and curved by the latex. He dropped his head in a groan, Ultron's head tilting very slightly to the side until Tony let out a sharp gasp as the machine's fingertip curved to ghost over his prostate, legs tightening in a quick jolt, optics scanning over him once more. His eyes narrowed as he tried to evaluate Stark's condition, unclear of what his vital scan was showing—without a chemical read he wouldn't be sure, and even with one he still couldn't be. Was it just instinct? This just became much more than psychological torment. 

He skated the edge of the human's swelling tissue with each slow thrust in and out of his body, Tony growing more and more vocal with each passing swipe, which he attributed to heightening of sexual arousal. After some time of this he pressed a second finger into him, flesh surprisingly pliant. Tony cried out as he did, pleasure spilling up his nervous system, sweat dampening his collar, and chest heaving. The rounded tips traced synchronized patters within Stark, legs starting to quiver consistently, a heated moan escaping him as his cock pulsed, precum streaming down his achingly hard flesh. Ultron looked down with the closest expression he could manage to a quirked eyebrow and delight. Tony's hands hesitantly reached for the other's clavicle structure, fingers threading over it as he held himself steady, eyes opening as Ultron's gaze found his, digits giving a firmer push just to watch his eyelids flutter again, lust and adoration clouding Stark's expression as he stared into those almost blinding lights. 

“Can you hold yourself up?” His voice was barely audible beyond their immediate space, Tony nodding quickly, hands gripping the metal tighter. Ultron's right hand transferred more of the weight into his left palm, releasing Stark's leg to reach between them. His thumb glided up the slick underside of Tony's cock, an 'ah' following as more fluid spilled form him, digits keeping their calculated pace and movement within him, ridges and grooves serving each other better than either would have expected. His other hand closed tenderly around Stark's eager hardness, stroking him slower than Tony would have optioned for, but the sensation was incredible and he wasn't going to gripe. He could feel climax rushing towards him, a storm over the plains, and his whole body shook. 

“Ooh, my god,” he choked, “Fuck.” He dropped his head back into the pillar, orgasm spilling through his entire body, and it was so wonderfully holistic and intoxicating, and it seemed to drag on, stimulus only receding enough to keep it from becoming overwhelming. Eventually the sensation fell enough to be considered over, but the side effects would be with him for some time. He panted heavily, unclenching his hands from their metal support and flexing them to encourage blood flow, almost losing his balance before a freshly slicked hand caught him. He resisted looking up as long as he could, but curiosity, again, got the better of him. And the automaton was just watching him with no discernible expression, waiting, observing. He was certainly pleased, but his trouble in distinguishing the intent behind biological responses was weighing on him. 

After another once over of the man, and when his breathing had leveled out, he lowered him back down to his feet, though Tony wasn't quite ready for that and slumped down the stone to the floor, resting back against it with a heavy sigh. Ultron examined his hands, the stark contrast of mingling fluids and latex cover almost poetic. He peeled the layers away, dropping them next to Tony before starting to pace away. “Aren't you going to make me breakfast?” Tony breathed, the latent effects still obvious in his tone, but maybe he could stall the other long enough to figure out a way to get control of him.

He turned, paused, and walked back, lowering himself to one knee in front of Tony, optics tracing over every detail of the disheveled man. “I appreciate what you're trying to do, but again, it's a futile effort. I have schemes I need to be wringing my hands about, but I'm far from done with you.” He stood and walked away, taking his leave through an already broken out area of the far wall.

“Don't make me call Optimus Prime!” he called after him, but he was already gone. The room was still, and even the lights seemed dimmer. The faint patter of tracked wheels rolled closer, and Tony looked over to see a small towel in the grasp of Dum-E, lowered to his level. “...thanks.”


End file.
